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Transcript
Hunting Is Not The Cure But The Cause Of
Overpopulation And Starvation
From Peter Muller
To see exactly how hunting is destructive to an ecosystem, let’s look at a
specific game animal. Probably the most widely hunted animal in North
America is one of the common species of deer (white-tailed, mule deer, or
black-tailed with an aggregate of about 50 subspecies)
Let’s consider a naturally segmented area has sufficient browse to feed a
deer herd of 400 animals. Wildlife biologists would describe this by saying
that the biological carrying capacity of the area for deer is 400. A territory
has associated with it a carrying capacity for each species that has naturally
evolved there. Nature has mechanisms in place to ensure that the carrying
capacity that is appropriate for that species is not exceeded. What would
happen if the deer population increased to substantially over 400 in one
year?
Let’s say that with all normal control mechanisms in place (including natural
predators) the herd size reaches 500 healthy individuals. At the start of the
next rut, several mechanisms would kick in to ensure a smaller amount of
fawns the following year. If deer are hungry (not starving, but not well fed
either), the sex drive of the bucks declines and the does stop ovulating or
become receptive less frequently than they would if plenty of browse is
available. Since the browse is now insufficient to feed all 500 animals, a
portion of the deer population would not reproduce during that season. With
the normal die-off during the winter and the smaller than normal birth during
the spring, the total population would be reduced to less that 500.
Within a few seasons the populations would again stabilize around the
capacity of the territory. If the herd size dropped substantially below the
carrying capacity (say to 300), other natural mechanisms would kick in (for
example, does who have lots of browse during the rut are more likely to
have twins or triplets) to bring the population back up to the normal carrying
capacity of 400. Many other mechanisms, some simple and some fairly
involved and not yet completely understood, are used by nature to maintain
the population at the carrying capacity.
These mechanisms with which the species have evolved have, built into
them, assumptions that have been true for millions of years. Human hunting
totally destroys some of these assumptions
Normally, left to their own devices, the sex ratio of male to female animals
is about 50-50. Deer are born about evenly male and female. Most “sport” or
“trophy” hunters prefer to take bucks rather than does. Almost state game
agencies mandate that during the regular hunting only bucks (antlered deer)
and no does are shot. Under certain extreme conditions, where a deer
population has totally mismanaged for years “doe permits” are issued in
addition to the regular deer tags in a desperate attempt to mitigate the mess
that the agencies have created over the years. This policy of shooting out
bucks distorts the gender ratio of the population.
Let see what happens when that ratio changes from 50-50 ratio to 80-20 –
leaving four times as many does as bucks This is not at all uncommon. In
Texas and the Southwest, in general, years of mismanagement have pushed
the doe to buck ratio as high as 10:1 in some areas.
Let’s look at two herds – one unhunted with the gender ratio intact at 50/50
and one hunted and one hunted with the gender ration skewed to 80/20.
Otherwise everything is the same both herds live in an area where there is
sufficient browse for 400 animals. Nature’s mechanisms that adjust the
population to the browse will now miscalculate and cause an overpopulation
for the hunted herd but leave the unhunted herd stable at 400 animals.
Based on 50-50 ratio, a herd of 400 will consist of 200 bucks and 200 does.
Normal browse conditions signal to each doe to give birth to a single fawn.
Assuming a winter die-off of 100 deer. The surviving herd would consist of
150-buck and 150 does. Each of the 150 does would give birth to 150 fawns.
The herd sized, including the new 150 fawns is now 450. Fawns have about
a 2/3 chance of surviving until the next fall because they are subject to more
predation than adult deer; for example, coyotes will predate on fawns but
rarely on fully grown deer. Other mortality rates are also higher for fawns
that adult deer. At the next rut the herd is back to 400.
Based on an 80/20 gender ratio, a 100 animal winter die-off, and normal
browse conditions there will 240 does and 60 bucks in the surviving herd.
The 240 does will give birth to 240 fawns of which 160 will survive. At the
next rut the herd size is now 460 instead of 400. That’s a 15% increase over
the normal her size. A few successive seasons like that and the herd
approaches conditions where massive, catastrophic starvation and die-offs
are inevitable.
Hunting is not the cure but the cause of overpopulation and starvation. Luke
Dommer, the founder of the Committee to Abolish Sport Hunting, has
proposed to several times to various state wildlife agencies that if they are
serious about using hunting as a population control tool in areas where the
sex ratio is already badly distorted, they should institute a doe-only season.
(Taking no bucks but only does until the ratio is again stabilized at 50:50).
All agencies have rejected that proposal – thereby giving up any pretense of
ecologically motivated sound wildlife management. They quite consciously
and openly state that they are in business to provide the maximum number of
live targets to hunters each year.
The state agencies encourage the destruction of the naturally evolved
ecosystem by encouraging human hunting that balloons the population of the
game species at the expense of the non-game species. Management
techniques, in addition to sex-ratio distortion, include removal of natural
predators (e.g. wolves, coyotes, panthers, bears) altering the natural habitat
to provide additional browse for game species and destroying the habitat of
non-game species (e.g. clear-cutting and/or burning areas and sowing them
with oats for deer at the expense of rabbits, voles, various reptiles and
amphibians – and many other non-games species.)
Things sometimes go totally haywire if a species is introduced into an
ecosystem where it didn’t evolve. Biologists call such an organism an
“exotic” animal or plant. If the exotic animal is a prey species, it may have
no defenses against a local predator and be totally wiped out in a very short
time. On the other hand, it may not have any local predators and
consequently proliferate beyond the carrying capacity of the territory,
causing catastrophic die-off through starvation.
If an exotic predator is introduced, the exotic species itself may die out if
there is no suitable local prey. Or, it may cause the extinction of local prey
species who have no defenses against the exotic predator. Or, it may cause
the extinction of local predators if it is more successful and out-competes the
local predator species in taking the prey.
Numerous examples of the consequence of introduction of exotic organisms
within environments where they have not evolved can be cited: The
introduction of snakes into Guam during World War II to control the rat
population nearly wiped out several indigenous bird species; introducing
trout for sport fishing into Lake Titicaca in Peru in the 1930s wiped out
about 25 species of local fish. Those fish were not found anywhere else in
the world. There are hundreds of examples where the introduction of an
exotic species had a deleterious effect on an ecosystem.
The wildlife management agencies defy sound procedure by such practices
as introducing exotic game species into areas and then distorting the habitat
to favor their survival at the expense of native species that have evolved in
the area. e.g. stocking an area with pheasants –an Asian bird—and cutting
tall timber trees needed by native raptors for perches.
The activity of human hunting is not and never has been a sustainable,
mutually beneficial, predator, prey relationship. Human hunting techniques,
even the most primitive ones, are far too efficient to meet the conditions
required of a natural predator-prey relationship. In modern times, with new
technology, the efficiency becomes totally lopsided so as to cause instant
habitat degeneration. Add to this the conscious mismanagement of habitat to
further degrade and obviate all natural corrective measures.
Using techniques such as sex-ratio distortion, habitat manipulation, the
removal of natural predators and the introduction of exotic game species
destroys biodiversity. The goal is to maximize the number of targets for
human hunting, thereby destroying the naturally evolved ecosystems and
putting them at the brink of total collapse.
The number of animals of game species (native and exotic) is maximized at
the expense of all others. The naturally evolved mechanisms that insure
biodiversity are short-circuited.
The only way that these ecosystems can recover is to prohibit human
hunting and all other forms of non-sustainable consumptive uses of these
animals. We should allow for the unfettered reintroduction and reimmigration of predators (which is occurring naturally). Stop “managing”
the environment of those areas. When it comes to managing the
environment, our knowledge is inadequate to do an even passable job. Even
given an ethically sound motivation, which the state agencies now lack, we
simply don’t know enough to do a better job than nature.
Rather than playing God, we ‘re acting more like the three stooges, when it
comes to managing ecosystems. For the sake of life on earth, we must not
allow the hunting and gun-manufacturing lobbies to continue to dictate
wildlife management policies.
BIB: http://www.all-creatures.org/aip/nl-26mar2002-hunting.html